A breakdown reel or spool typically includes separate flange and barrel portions that are locked together during use and that may be separated when desired. A number of forms of breakdown spools are known.
U.S. Pat. No. 7,510,138 and US 2009/0261195 to Chiorgno et al show various breakdown spool constructions including a two-piece locking mechanism to secure the cylindrical barrel to the flange. The locking mechanism includes keyed elements that project through the wall of the flange. An inside section is engaged within the end of the barrel and includes internal structures that mate with the keyed elements on the outside section. A stop is provided on the outside wall of the inside section of the barrel. Rotation of the inside section with respect to the outside section causes a mating engagement of the keyed elements and locks the barrel and flange.
US 2007/0262192 and US 2007/0181739 to Derendal show breakdown spool constructions with outwardly projecting locking tabs on the ends of the barrel. The tabs are inserted into separate recesses within the wall of the flanges. A knob is formed on each of the locking tabs and is positioned to engage in a slot upon rotation of the barrel relative to the flange. Flexible retaining members are formed on the ends of the barrel, each with a nub extending axially outward. The nubs engage with receptacles in the surface of the flange.
U.S. Pat. No. 6,089,500 to Hafner shows a breakdown spool having a bayonet coupling between the hub and the flange. A series of retaining elements are positioned on the outside surface of the end of the barrel. The retaining elements lock with a corresponding series of inwardly projecting locking elements formed on the wall of a circular recess in the flange.
U.S. Pat. No. 3,468,492 to Cragg shows a winding spool structure with at least one flange releaseably locked to the barrel. A central hub is formed inwardly of the winding surface of the barrel. The hub includes a series of spaced lugs that engage within slots formed adjacent to a central opening in the flange. Rotation of the lugs into a locking position secures the flange to the barrel. Flexible detent members are formed in the surface of the flange. The detents engage with notches formed on the end of the barrel.